President Barack Obama advised Donald Trump on Tuesday to stop whining about voter fraud ahead of the elections.

Trump has urged his supporters to monitor certain areas on election day to prevent what he believes could be a rigged election.

“I have ever seen in my lifetime or in modern political history any presidential candidate trying to discredit the elections and the election process before the votes take place,” Obama said, during a press conference in the Rose Garden with Italian Prime Minister Matteo Renzi.

“Every expert, regardless of political party, regardless of ideology, conservative or liberal, who has ever examined these issues in serious ways will tell you instances of significant voter fraud are not to be found,” Obama said.

He also said that it would be irresponsible to propagate the notion that in a state like Florida, for example — which has a both a Republican governor and Republican appointees facilitating elections there — Trump could lose because of “those people you have to watch out for.”

Obama added that Trump’s behavior “doesn’t really show the leadership and toughness you’d want out of a president.

“You start whining before the game’s even over?” Obama asked.

“If, whenever things are going bad for you and you lose, you start blaming somebody else? You don’t have what it takes to do this job.”

Obama again emphasized that “there is no serious person out there who would suggest somehow that you could even rig America’s election, in part because they’re so decentralized.”

He added that no such evidence exists that questionable voting practices have occurred in the past.